The Analysis Of Clinical And Epidemiologic Characteristics Of Low-back Pain Of Coal Miners

Objective:This study was designed to descriptive and analysis the characteristics and related effects of low back pain in coal miners through cross-sectional epidemiology methods and to identify adverse ergonomic factors of the whole work system. Then elevate the relationships between physical load exposure effects and the low back pain and provided guidelines for improvements of working conditions of coal miners and for prevention of low back pain in coal mining workers.Methods:1. Subjects for investigation:From June to October in 2008, Coal miners of Fenghuangshan Coal Mining who were adopted to the physical examination center of General Hospital of Jincheng Coal Mining Group Co.Ltd were divided into five groups:tunneling group,recovery group,handling group,electrical group and logistics group.2531 of them were selected for this study randomly according to their types of work. All of the workers must be employed for more than 12 months and without any serious internal diseases and trauma.2. Physical examination of the workers:Physical examinations were conducted by orthopedic surgeons and the examinations include palpation, sports function, sensory function and neural reflection.3. Questionnaire:The questionnaire was based on Nordic Questionnaire (Northern European standard questionnaire for the analysis of musculoskeletal symptoms) and adopted additional questions such as the main features, timing, and contributing factors of the low back pain。All the questions were conducted by trained examiners.4. Measurements of the intensity of the pain:2 different methods, i.e. visual analogue scales (VAS), and 6-point behavioral rating scales (BRS-S) were used to measure the intensity of the pain in workers with low back pain within past one year.5. Ergonomic analysis of work place:Adverse ergonomic factors of the work places of 5 groups were identified with ergonomic work place analysis. The analysis included 14 different items:working site, general physical activity, lifting, work posture and movement, accident risk, job content, job restrictiveness, worker communication, decision making, repetitiveness of work, attentiveness, lighting, humid environment and noise.6. Analysis of postural and load in coal miners:The activities of workers of five groups were observed with split-second observations. The work postures were analyzed with adapted OWAS analysis system with additional work phase and work tool related codes which recommended by Finnish Institute of Occupational Health. The weight of each individual posture component is then calculated, and finally the individual posture and composite posture levels are determined.Results:1. The prevalence of the low back pain:Results of orthopedic examination showed that the workers had normal sensory and normal muscle strength. Only 3 positive cases were identified in straight leg lifting and extra-intense tests. The total prevalence rate of occupational low back pain was 45.1%, with the highest 49.5% in handling workers.2. Intensity of the low back pain:the intensities measured from 2 different methods were all below medium level.3. Inducing and adverse factors of low back pain:Overexertion, repetition work and bad posture were the top 3 adverse factors and with a percentage of above 80% of over all factors. The results of regressive model analysis showed that history of past trauma, lifting work and humid environment were the adverse factors of occupational low back pain.4. Analysis results of work systems and postural:Workers of tunneling group had the most exposure to adverse factors including overexertion, heavy lifting, awkward work postures and movement, repetition work and noises.Conclusion:1. Among all coal miners, the workers of tunneling group,recovery group and handling group had the most serious low back pain symptoms. The induced factors included overexertion, repetition work and awkward work postures.2. The prevalence of occupational low back pain increases with the individual age and length of service.3. The adverse factors of low back pain included humid, noisy and windy environment, illumination time, smoking and the history of past trauma.